The present invention is generally related to washing machines and, more particularly, to a system based on inductive coupling for sensing spin speed and an out-of-balance (OOB) condition which can arise during the operation of the washing machine.
In a typical washing machine (such as a top or front-loading washing machine) the OOB condition can actually occur during a spin cycle, for example, when the articles to be cleansed, such as clothing and the like, bunch up asymmetrically at various locations in the basket for holding such articles. For various detrimental reasons the OOB condition is not desirable if left uninterrupted. For example, a tub which encloses the basket may violently strike the cabinet of the washing machine and thus cause damage either to the tub, the cabinet or both. Further, unacceptable stress forces can develop during the OOB condition that can affect the suspension mechanism of the washing machine as well as other components thereof such as the transmission or other suitable connecting device which links the motor of the washing machine to the spinning basket. Regardless of whether the OOB condition actually develops during any given spin cycle, it is useful to accurately sense or measure spin speed during the spin cycle. For example, this measurement can be used for determining transmission and/or motor performance under various load conditions. It is thus desirable to provide a system for sensing spin speed and for sensing any OOB condition which can arise in the washing machine. It is also desirable for this sensing system to be low cost and reliable, i.e., a robust sensing system which does not require elaborate logic to sense spin speed and any OOB condition in the washing machine, and which does not need frequent calibration or resetting.